How to make soil blocks

2" Soil blocks using Miracle-Gro Mix

I was first introduced to soil blocking in 1989 by author Eliot Coleman in his first book called The New Organic Grower. His ideas and methods on gardening attracted free spirited baby boomers of the 70's and 80's and alike to the idea of growing organically. I must admit that I was hooked and I started to make soil blocks using his well known recipe of compost, peat moss, garden soil, blood meal and other fertilizers.

The idea of soil blocking was well known to the British where the soil blocker was manufactured by Ladbrooke Soil Blocks and it really took roots when Eliot Coleman described how to make this gooey organic mix into square blocks with a hole in the top for seeding. This eliminated the need for plastic or styrofoam pots and made potting up really easy by using larger soil blocks.  Blockers are made in three sizes, 1/4" mini blocks, 2" blocks and 4" large blocks so planting up is easy. I must admit that the 2" block suited my purpose for a short term growing period of 4-6 weeks for cukes, beans and tomatoes. Eliot's original recommendation was to build a wooden box 20" long x 10" wide, open on one side for easy access in the garden, to hold 36 soil blocks 2" square. I still have them today.

Wood tray cleaned & ready

Making the blocks is relatively easy using Miracle-Gro potting mix which contains peat moss, fertilizer, and perlite for drainage. Mix lots of warm water with the potting mix until it runs out when squeezed with your hands. It will have a consistency of moist mud so wear gloves to keep your nails clean. Push the blocker into the mud/soil and twist until the blocker is full. Using a wood stick scrape the bottom to level the soil. Place the blocker on the tray and gently push the blocks out and repeat the process keeping the blocker very close to the previous blocks. There will be a 1/8" space between the blocks that air prunes the roots as the plant grows. I use an old bread knife to separate and lift the blocks when potting up or planting in the garden. Drop the seeds into the top holes and cover with a light dusting of soil and spray with a water bottle.

GBBQ greenhouse tray

I'm experimenting with a BBQ chicken tray/lid as a small greenhouse using the soil blocks. Wash out the container in hot soapy water and drill holes in the plastic lid. Instant greenhouse with humidity control! You can get 9-10 blocks into the tray with a little help and the tray keeps your window sill clean. The cukes germinated twice as fast than others not in the greenhouse!  Just pour water in the tray and the soil blocks will draw up the H20.

The acronym GBBQ (Greenhouse BBQ) may soon become synonymous with soil blocking! );  Try soil blocking, my friend!